Abstract :
The object of this paper is to stimulate interest in a piece of apparatus which, until comparatively recently, was practically unknown in this country. Its efficacy in preventing interruptions of supply under certain types of fault conditions has been for many years fully appreciated on the Continent, where even on underground networks it is regarded as indispensable by many supply authorities. Although the principles involved are briefly referred to for the benefit of those who are not familiar with the publications available dealing with the fundamental theory, the matter is dealt with from an operating rather than a theoretical point of view by drawing attention to a number of problems, many of them peculiar to this country, which arise when a Petersen coil is to be applied on a system originally intended to operate with the neutral solidly earthed; by suggesting convenient ways to obtain the information required by the makers for a coil or coils to suit any particular network; by dealing with a number of cases in which special measures are necessary; by explaining the means of tuning the coil to suit changing network conditions; by giving results obtained from coils in operation; and by comparing these results with those of solid or resistance earthing.
